阅读说明：本技术 一种硅基底3-6μm红外窗口片 (Silicon substrate 3-6 μm infrared window sheet ) 是由 潘安练 于 2020-06-01 设计创作，主要内容包括：本发明公开了一种硅基底3-6μm红外窗口片,所述红外窗口片以单晶硅为基底,所述基底两侧均镀有单层的增透膜,所述增透膜选自一氧化硅膜或氧化钇膜,本发明以单晶硅作为基底,选择一氧化硅或者氧化钇作为增透膜材料,意外的发现在特定的厚度下(一氧化硅增透膜的厚度为0.537-0.696μm,氧化钇增透膜的厚度为0.502-0.689μm),只需两侧均采用单层的增透膜结构,即可使红外窗口片在3-6μm的红外波段平均透过率≥90％,极值透过率≥98％；而在优选的方案中,所述红外窗口片在3-6μm的红外波段平均透过率≥90％,极值透过率≥99.6％。本发明采用单层增透膜却达到了现有技术中需要设置多层增透膜才能达到的红外窗口的使用效果。(The invention discloses an infrared window sheet with a silicon substrate of 3-6 mu m, wherein the infrared window sheet takes monocrystalline silicon as a substrate, two sides of the substrate are respectively plated with a single-layer antireflection film, and the antireflection film is selected from a silicon monoxide film or an yttrium oxide film; in the preferred scheme, the average transmittance of the infrared window sheet in an infrared band of 3-6 μm is more than or equal to 90%, and the extreme value transmittance is more than or equal to 99.6%. The invention adopts a single layer of antireflection film, but achieves the use effect of the infrared window which can be achieved only by arranging a plurality of layers of antireflection films in the prior art.)

1. A silicon substrate 3-6 μm infrared window sheet is characterized in that: the infrared window sheet takes monocrystalline silicon as a substrate, two sides of the substrate are respectively plated with a single-layer antireflection film, and the antireflection film is selected from a silicon monoxide film or an yttrium oxide film.

2. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the antireflection film is selected from an yttrium oxide film.

3. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the thickness of the silicon monoxide film is 0.537 to 0.696 mu m.

4. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the thickness of the yttrium oxide film is 0.502-0.689 μm, preferably 0.6-0.634. mu.m.

5. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the incidence angle of the antireflection film is 0 +/-5 degrees; the incident medium of the antireflection film is air; the central wavelength of the antireflection film is 4.5 +/-0.01 microns.

6. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the average transmittance of the infrared window sheet in an infrared band of 3-6 mu m is more than or equal to 90%, and the extreme value transmittance is more than or equal to 98%.

7. A silicon substrate 3-6 μm infrared window pane as claimed in claim 1, wherein: the preparation method of the infrared window sheet comprises the following steps:

step one, vacuumizing the vacuum chamber bottom to (0.9-1.0) E-3Pa, wherein the pre-melting film material is in a melting state, heating the deposition area to 150-; the film material is silicon monoxide or yttrium oxide,

and secondly, filling argon into the vacuum chamber, evaporating the film material by adopting an electron beam, depositing an antireflection film, bombarding the substrate by using an ion source to compact the film layer, controlling the evaporation rate to be 0.8-1nm/s, controlling the argon partial pressure to be (2.0-2.5) E-2Pa, and maintaining the vacuum degree of the vacuum chamber to be (2.1-2.6) E-2 Pa.

8. A silicon substrate 3-6 μm infrared window pane as claimed in claim 7, wherein: in the first step, the purity of the silicon monoxide is 99.99%, and the purity of the yttrium oxide is 99.99%.

9. A silicon substrate 3-6 μm infrared window pane as claimed in claim 7, wherein: in the second step, the voltage of the electron beam is-10 kV, and the current is 0.8-1A.

10. A silicon substrate 3-6 μm infrared window pane as claimed in claim 7, wherein: in the second step, the ion energy is 200-250eV, the ion beam current is 30-40mA, and the deviation of the ion distribution is 15-20%.

Technical Field

The invention belongs to the field of optical films, and particularly relates to a silicon substrate 3-6 mu m infrared window sheet.

Background

The 3-6 μm infrared window sheet is a commonly used infrared light source device for isolating the internal system of the detector from the external environment. At present, the period and cost for manufacturing the window sheet are limited by the selection of a substrate material and the selection of an antireflection film material in practical application, the conventional infrared antireflection film generally selects germanium and ytterbium fluoride as high-refractive index and low-refractive index materials, the designed number of layers is 6-8, the thickness is 2-3 microns, the preparation cost is high, the production time is long, and the large-scale popularization is not facilitated.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a silicon substrate 3-6 μm infrared window sheet with low cost performance and high transmittance.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention relates to an infrared window sheet with a silicon substrate of 3-6 microns, which takes monocrystalline silicon as a substrate, wherein two sides of the substrate are plated with a single-layer antireflection film, and the antireflection film is selected from a silicon monoxide film or an yttrium oxide film.

Preferably, the antireflection film is selected from an yttrium oxide film.

Preferably, the thickness of the silicon monoxide film is 0.537 to 0.696 μm.

Preferably, the thickness of the yttrium oxide film is 0.502-0.689 μm, preferably 0.6-0.634. mu.m.

In the invention, the thickness of the antireflection film is crucial, the thickness range of the antireflection film is controlled within the above range, and the multilayer film can achieve better transmittance than the multilayer film in the prior art by only adopting a single layer film.

In a preferred embodiment, the incident angle of the antireflection film is 0 ° ± 5 °.

In a preferred scheme, the incident medium of the antireflection film is air.

In a preferred embodiment, the central wavelength of the antireflection film is 4.5 ± 0.01 μm.

In a preferable scheme, the average transmittance of the infrared window sheet in an infrared band of 3-6 microns is more than or equal to 90%, and the extreme value transmittance is more than or equal to 98%.

Further preferably, the average transmittance of the infrared window sheet in an infrared band of 3-6 μm is more than or equal to 90%, and the extreme value transmittance is more than or equal to 99.6%.

More preferably, the average transmittance of the infrared window sheet in an infrared band of 3-6 μm is more than or equal to 92%, and the extreme value transmittance is more than or equal to 99.65%.

Preferably, the wavelength range of the light suitable for the infrared window sheet is 3-6 μm.

Further preferably, the infrared window sheet is suitable for the light wavelength range of 3.7-4.8 μm. The infrared window sheet has the optimal transmittance in the infrared band of 3.7-4.8 mu m.

Preferably, the preparation method of the infrared window sheet comprises the following steps:

step one, vacuumizing the vacuum chamber bottom to (0.9-1.0) E-3Pa, wherein the pre-melted film material is in a molten state, heating the deposition area to 150-170 ℃, and keeping the temperature for 20-30 min; the film material is silicon monoxide or yttrium oxide,

filling argon into the vacuum chamber, evaporating the film material by adopting an electron beam, depositing an antireflection film, bombarding the substrate by using an ion source to compact the film layer, controlling the evaporation rate to be 0.8-1nm/s, controlling the argon partial pressure to be (2.0-2.5) E-2Pa, maintaining the vacuum degree of the vacuum chamber to be (2.1-2.6) E-2Pa,

in the actual operation process, the surface of the single crystal silicon is firstly wiped, the wiped lens is placed in a lens support, and the lens support is placed on a workpiece disc of the existing film plating machine; the solution used for wiping is a mixed solution of ethanol and diethyl ether, and the volume ratio of the ethanol to the diethyl ether in the mixed solution is 6-8: 4-2.

Further preferably, in the first step, the purity of the silicon monoxide is 99.99%, and the purity of the yttrium oxide is 99.99%.

In practice, silicon monoxide or yttrium oxide is placed in an electron beam crucible.

Preferably, in the second step, when the film material is SiO and the thickness of the deposited antireflection film reaches 0.537-0.696 μm, the electron gun is turned off, and when the film material is yttria and the thickness of the deposited antireflection film reaches 0.502-0.689 μm, the electron gun is turned off.

Further preferably, in the second step, a quartz crystal film thickness controller is used for controlling the evaporation rate.

Further preferably, in the second step, the voltage of the electron beam is-10 kV, and the current is 0.8-1A.

Further preferably, in the second step, the ion energy is 200-250eV, the ion beam current is 30-40mA, and the ion distribution deviation is 15-20%.

In the actual operation process, after an antireflection film is plated on one side of the surface of the substrate, the substrate is taken out to be wiped and the other side is plated again.

Under the control of the process conditions, a compact and ideal film layer with the required thickness can be obtained, so that the refractive index of the material conforms to a theoretical value, and excellent transmittance is obtained under the synergistic matching of the thickness and the refractive index.

The advantages and effects are as follows:

according to the invention, monocrystalline silicon is used as a substrate, silicon monoxide or yttrium oxide is selected as an antireflection film material, and the discovery that under a specific thickness (the thickness of a silicon monoxide antireflection film is 0.537-0.696 μm, and the thickness of an yttrium oxide antireflection film is 0.502-0.689 μm), the average transmittance of an infrared window sheet in an infrared band of 3-6 μm is more than or equal to 90%, and the extreme value transmittance is more than or equal to 98% can be realized only by adopting a single-layer antireflection film structure on two sides; in the preferred scheme, the average transmittance of the infrared window sheet in an infrared band of 3-6 μm is more than or equal to 90%, and the extreme value transmittance is more than or equal to 99.6%. The invention adopts a single layer of antireflection film, but achieves the use effect of the infrared window which can be achieved only by arranging a plurality of layers of antireflection films in the prior art.

The infrared window sheet provided by the invention can be applied to an infrared detection system with the thickness of 3-6 microns, and has the advantages of simple coating design, common coating material selection and high film layer firmness, so that the manufacturing period and cost of the window sheet are greatly reduced, and the expanded production is facilitated.

Drawings

FIG. 1 is a schematic view of the structure of a window sheet of the present invention; wherein, 1, monocrystalline silicon, and 2, antireflection film.

FIG. 2 is a chart of a silicon wafer without plating an antireflection film;

FIG. 3 is a spectrum of a single-layer SiO double-coated wafer of example 1;

FIG. 4 is a spectrum of a single-layer SiO double-coated in example 2;

FIG. 5 is a spectrum of a single-layer SiO double-coated in example 3;

FIG. 6 is a spectrum of a single-layer SiO double-coated in example 4;

FIG. 7 is a spectrum of yttrium oxide coated on both sides with a single layer in example 5;

FIG. 8 is a spectrum of yttrium oxide coated on both sides with a single layer in example 6;

FIG. 9 is a spectrum of yttrium oxide coated on both sides with a single layer in example 7;

FIG. 10 is a spectrum of yttrium oxide coated on both sides with a single layer in example 8;

FIG. 11 is a spectrum of thickness of 0.50 μm when SiO is used as the coating material in example 9;

FIG. 12 is a spectrum of 0.75 μm thick SiO film used as a coating material in example 9;

FIG. 13 is a spectrum of a thickness of 0.45 μm with yttrium oxide as a coating material in example 9;

FIG. 14 is a spectrum of a film thickness of 0.75 μm formed using yttrium oxide as a coating material in example 9.

Detailed Description

As shown in FIG. 1, a silicon substrate 3-6 μm infrared window sheet, the window sheet uses single crystal silicon as a substrate, and both sides of the substrate are plated with a single-layer antireflection film structure.

According to the invention, the monocrystalline silicon 1 is used as a substrate, the silicon monoxide or the yttrium oxide is used as a coating material, and the two sides of the substrate are both plated with the single-layer antireflection film structure 2, so that the period and the cost for manufacturing the window sheet are greatly reduced.

The thickness of the film layer is 0.537 to 0.696 μm when the anti-reflection film is a silicon oxide material, and the thickness of the film layer is 0.502 to 0.689 μm when the anti-reflection film is an yttrium oxide material.

The invention uses silicon monoxide and yttrium oxide as film materials which are important factors for designing a simple antireflection film, and the average transmittance of 3-6 mu m after double-sided coating is more than 90 percent.

The infrared window sheet has the advantages that the two sides of the substrate are coated with the single-layer films, the adopted antireflection film material is more excellent, the film layers are simplified, and meanwhile, the transmittance is better. The average transmittance of the infrared window sheet is more than 90%, and the extreme value transmittance is more than 98%.

The transmittance of the silicon oxide material and the yttrium oxide material which are used as antireflection films can be greatly improved.

The thickness of the single-crystal silicon 1 as a base is in the range of 3 to 50 mm in diameter and 0.1 to 5 mm in thickness.

The incident angles of the antireflection film structures 2 on both sides of the window sheet are both defined to be between 0 ° ± 5 °.

The invention relates to a preparation method of a silicon substrate 3-6 mu m infrared window sheet, which comprises the following steps:

the method comprises the following steps: preparing a substrate: wiping the surface of the monocrystalline silicon, placing the wiped lens into a wafer support, and placing the wafer support on a workpiece disc of an existing film coating machine.

Wiping in the step one, wiping the surface of the monocrystalline silicon by using a solution prepared by matching ethanol and diethyl ether in a volume ratio of (6-8) to (4-2); the antireflection film material is silicon monoxide or yttrium oxide;

the purity of the silicon monoxide material is 99.99 percent; the purity of the yttria material was 99.99%.

Step two: preparation before plating: placing the anti-reflection film material in an electron beam crucible, vacuumizing the background of the vacuum chamber, and pre-melting the anti-reflection film material in a molten state.

And the vacuumizing condition in the second step is that the background of the vacuum chamber is vacuumized to (0.9-1.0) E-3Pa, the temperature of a deposition area is 150-170 ℃, and the constant temperature is kept for 20-30 min.

Step three: film coating: coating by adopting a vacuum electron beam evaporation method;

two sides of the monocrystalline silicon substrate are respectively plated with 1 layer of antireflection film structure 2, and two sides are plated with films;

setting the thickness of the coating film, wherein the thickness of the film layer is 0.537 to 0.696 mu m when the antireflection film is a silicon oxide material, and the thickness of the film layer is 0.502 to 0.689 mu m when the antireflection film is an yttrium oxide material.

The third concrete step is:

step a: presetting coating conditions before coating; the coating conditions of the step a are that the central wavelength of the antireflection film is 4.5 +/-0.01 mu m, the incident angle range is 0 +/-5 degrees, and the medium air is incident.

Step b: controlling the evaporation rate of the anti-reflection film material by using a quartz crystal film thickness controller; and b, controlling the evaporation rate to be 0.8-1nm/s by the quartz crystal film thickness controller, setting the voltage of an electron beam to be-10 kV, the current to be 0.8-1A, the argon partial pressure to be (2.0-2.5) E-2Pa, maintaining the indoor vacuum to be (2.1-2.6) E-2Pa, and controlling the argon filling amount to be 20-40 SCCM.

Step c: collecting electron beam spots on the material, heating to a glowing state, opening a baffle plate, and starting film coating; bombarding the film layer by using a Hall ion source to increase the compactness of the film layer.

And c, ion energy adopted by the Hall ion source in the step c is 200-250eV, ion beam current is 30-40mA, and ion distribution deviation is 15-20%.

As shown in FIG. 2, the transmittance of the silicon wafer without the antireflection film was only 69.98% @ 4.5. mu.m.